EP0510258B1 - Method of making an insulating member - Google Patents
Method of making an insulating member Download PDFInfo
- Publication number
- EP0510258B1 EP0510258B1 EP91121857A EP91121857A EP0510258B1 EP 0510258 B1 EP0510258 B1 EP 0510258B1 EP 91121857 A EP91121857 A EP 91121857A EP 91121857 A EP91121857 A EP 91121857A EP 0510258 B1 EP0510258 B1 EP 0510258B1
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- EP
- European Patent Office
- Prior art keywords
- layer
- insulating layer
- chromium oxide
- oxide containing
- nitride
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
- H01B7/29—Protection against damage caused by extremes of temperature or by flame
- H01B7/292—Protection against damage caused by extremes of temperature or by flame using material resistant to heat
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
- H01B3/10—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances metallic oxides
- H01B3/105—Wires with oxides
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12542—More than one such component
- Y10T428/12549—Adjacent to each other
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12576—Boride, carbide or nitride component
Definitions
- the present invention relates to an insulating member which is applicable to an interconnection wire or a wire for winding in a high vacuum apparatus or an apparatus for a high temperature.
- An insulated wire may be applied to equipment such as heating equipment or a fire alarm, which requires safety under a high temperature.
- An insulated wire is also employed in an automobile under environment which is heated to a high temperature.
- Such an insulated wire is generally formed by a conductor which is coated with heat resistant organic resin such as polyimide or fluororesin.
- an insulated wire comprising a conductor which passes through an insulator tube of ceramics, an MI cable comprising a conductor which passes through a tube of a heat resistant alloy, such as stainless steel alloy, filled up with fine particles of a metal oxide such as magnesium oxide, or the like.
- a glass braided tube insulated wire employing an insulating member of glass fiber fabric or the like is known as an insulated wire having high heat resistance and flexibility.
- an insulated wire coated with organic resin can maintain its insulability merely up to a temperature of about 2001 ⁇ 2C at the most. Therefore, such an insulated wire cannot be used when insulability is required under a high temperature of at least 2001 ⁇ 2C.
- the insulated wire which is improved in heat resistance with an insulator tube of ceramics is inferior in flexibility.
- the MI cable which is formed by a heat-resistant alloy tube and a conductor, is increased in outer diameter.
- the MI cable has a relatively large section with respect to electric energy which is allowed by the conductor passing through the heat-resistant alloy tube. While it is necessary to bend the heat-resistant alloy tube at a prescribed curvature in order to apply the MI cable to a wire for winding which is coiled on a bobbin or the like, such bending operation is difficult. When the MI cable is coiled, further, it is difficult to improve winding density due to the large diameter.
- the glass fiber When the glass braided tube insulated wire is arranged in a prescribed configuration, the glass fiber generates glass dust, which may serve as a gas adsorption source.
- glass dust When the glass braided tube insulated wire is employed under environment which requires a high degree of vacuum, therefore, it is impossible to maintain the high degree of vacuum due to the gas adsorption source provided by the glass dust.
- EP-A-0 416 131 discloses an insulated electric wire comprising a base material having an outer surface and containing a conductor, a chromium oxide containing layer formed on the outer surface of the base material, and an oxide insulating layer formed on the chromium oxide layer.
- the oxide insulating layer is formed by applying a precursor solution of a metal oxide based on the sol-gel method or an organic acid salt pyrolysis method.
- GB-A-2 182 800 discloses a flat cable comprising a plurality of metallic conductors, a coating of an insulating compound and a continuous polymeric insulating layer.
- the compound may be nitride.
- the oxide or nitride coating is provided by sputtering.
- the present invention has been proposed in order to solve the aforementioned problems of the conventional insulated wires, and an object thereof is to provide an insulated wire, which has advantages of: (a) high insulability under high-temperature environment; (b) excellent flexibility; (c) provision of no gas adsorption source; and (d) selectability for combination of a base material and an inorganic insulating layer which is applicable in various ways.
- An insulated wire prepared according to the method of the present invention comprises a base material, a chromium oxide containing layer, and a nitride insulating layer.
- the base material has an outer surface, and contains a conductor.
- the chromium oxide containing layer is formed on the outer surface of the base material.
- the nitride insulating layer is formed on the chromium oxide containing layer. This nitride insulating layer is formed by thermal decomposition of an organic metal polymer.
- the chromium oxide containing layer is preferably formed by an electrochemical method such as electrolytic plating or electroless plating.
- the chromium oxide containing layer serving as an underlayer for the nitride insulating layer preferably has an outermost layer which serves as an adhesion layer for the nitride insulating layer.
- the outermost layer is preferably prepared from CrO 3-x (1.5 ⁇ x ⁇ 2.5).
- the outermost layer of the chromium oxide containing layer, which is formed by an electrochemical method, is defined by such a layer of chromium oxide having excellent adhesion.
- the nitride insulating layer preferably contains silicon nitride and/or aluminum nitride.
- the base material is preferably made of copper or copper alloy, in view of high conductivity and a low cost.
- the base material may be formed by a conductor which is coated with nickel, chromium, silver, iron or iron alloy such as stainless steel, or titanium or titanium alloy.
- a layer of such a metal or alloy can be formed on a surface of copper or copper alloy by plating or a cladding method.
- a metal oxide insulating layer may be formed by a sol-gel method between the chromium oxide containing layer and the nitride insulating layer.
- the sol-gel method is a method of forming a sol of a precursor for a metal oxide by hydrolyzing and dehydrating/polycondensing a hydrolyzable compound having metal-oxygen-organic group bonding such as metal alkoxide or metal carboxylic acid ester and forming a metal oxide through a gel by appropriate heat treatment.
- a chromium-plated layer is formed on a conductor of copper or copper alloy as an excellent adhesion layer.
- a chromium-plated layer is to be coated with an insulating nitride ceramics layer of silicon nitride or the like which is prepared by heat treatment of a precursor solution for a metal oxide, however, such nitride ceramics hardly exhibits adhesion to the chromium-plated layer.
- the inventors have empirically found this fact.
- an insulated wire is prepared by directly forming a thin film of ceramics such as a nitride on the surface of a conductor of copper or the like, the thin film of ceramics, serving as an insulating layer, has insufficient adhesion to the base material.
- a chromium oxide containing layer having an outermost layer of chromium oxide is formed on the outer surface of a base material.
- a layer of insulating nitride ceramics having excellent adhesion is provided on the outermost layer of the chromium oxide containing layer.
- the chromium oxide containing layer is preferably formed by an electrochemical method, as hereinabove described.
- the electrolytic bath is preferably prepared by adding a small amount of organic acid to an aqueous solution of chromic acid.
- This electrolytic bath is different from a Sargent bath, mainly containing chromic acid and sulfuric acid, which is known as an electrolytic bath generally employed for chrome plating, as follows:
- Mineral acid which is mixed into an electrolytic bath is adapted to dissolve chromium oxide formed on a plated surface in electroplating. Therefore, a glossy metal chromium layer is plated through a Sargent bath.
- a chromium oxide containing layer formed in the present invention on the other hand, it is necessary to preferentially deposit and apply chromium oxide. According to the present invention, therefore, organic acid is employe din place of mineral acid.
- the as-formed layer which is mainly composed of chromium oxide, preferably has a rough surface, since the same is further coated with an intermediate layer such as a nitride insulating layer or a metal oxide insulating layer.
- an intermediate layer such as a nitride insulating layer or a metal oxide insulating layer.
- such preferential formation of chromium oxide and the rough surface can be attained by performing plating at a current density which is different from that for general gloss plating.
- gloss plating is performed at a current density of 10 to 60 A/dm2, depending on the treatment temperature.
- a current density of 100 to 200 A/dm2 is employed to form a chromium oxide containing layer having a rough surface.
- the nitride insulating layer is formed by thermally decomposing an organic metal polymer.
- an organic metal polymer can be prepared from alkyl aminosilicate such as polysilazane, for example. This heat treatment is preferably performed under an atmosphere of ammonia or nitrogen jet. The organic metal polymer can be substantially completely decomposed into a nitride by such heat treatment at a temperature of about 700°C.
- the chromium oxide containing layer is formed on the outer surface of the base material, and the nitride insulating layer is formed on the chromium oxide containing layer.
- the chromium oxide containing layer is excellent in adhesion to the base material, as well as to a layer such as the nitride insulating layer or a metal oxide insulating layer. Therefore, high adhesion can be attained as compared with a case of directly forming a nitride insulating layer or a metal oxide insulating layer on the outer surface of the conductor.
- the insulated wire according to the present invention has heat resistance and insulability, as well as excellent flexibility.
- the nitride insulating layer formed on the chromium oxide containing layer has a smooth outer surface. Thus, it is possible to obtain a high breakdown voltage which is proportionate to the film thickness and reduce a gas adsorption source, whereby the insulated wire provides a high degree of vacuum in a high vacuum apparatus.
- the nitride insulating layer is formed on the chromium oxide containing layer. Since any type of nitride insulating layer can be formed on the chromium oxide containing layer with excellent adhesion, it is possible to combine a nitride insulating layer which is suitably applied in various ways.
- a nickel-plated layer 2 is formed on the outer surface of a copper wire 1.
- a chromium oxide containing layer 3 is formed on the nickel-plated layer 2.
- a nitride insulating layer 4 prepared by heat treating a precursor for a metal nitride is provided on the chromium oxide containing layer 3.
- the nitride insulating layer 4 was made of silicon nitride. Further, a layer defined by the chromium oxide containing layer 3 and the nitride insulating layer 4 was about 5 »m in thickness.
- the breakdown voltage of this insulated wire was 500 V under the room temperature, and 300 V under a temperature of 800°C.
- a chromium oxide containing layer was coated with an organic metal polymer, and thermally decomposed to form a nitride insulating layer.
- Fig. 2 shows this insulated wire.
- a stainless steel layer 12 is formed on the outer surface of a copper wire 11 as a clad layer.
- a chromium oxide containing layer 13 is formed on the stainless steel layer 12.
- a nitride insulating layer 14 is formed on the chromium oxide containing layer 13.
- Nitride particles 15, which are aluminum nitride particles, are dispersed in the nitride insulating layer 14.
- a layer defined by the chromium oxide containing layer 13 and the nitride insulating layer 14 was 12 »m in thickness.
- the breakdown voltage of this wire was 900 V under the room temperature, and 700 V under a temperature of 800°C.
- this insulated wire was wound on the outer peripheral surface of a cylinder of 15 cm in diameter, no crack was caused in the insulating layer.
- Electrolytic plating was performed on the surface of a nickel-plated copper wire in a similar manner to Example 1, to form a wire of 0.5 mm in wire diameter having a chromium oxide containing layer on its surface.
- the chromium oxide containing layer was 1.0 »m in thickness.
- a solution for forming a metal oxide insulating layer was prepared by a sol-gel method.
- Nitric acid was added to a solution, containing tetrabutyl orthosilicate, water and isobutyl alcohol in mol ratios of 8:32:60, at a rate of 3/100 mol.
- This mixture was heated at a temperature of 80°C for 2 hours, to prepare a coating solution.
- This solution was applied onto the aforementioned wire having a chromium oxide containing layer on its surface and heated in the atmosphere at 600°C for 15 minutes, to form a metal oxide insulating layer of 4 »m in thickness.
- the breakdown voltage of this wire having a metal oxide insulating layer on its surface was 400 V, and it was impossible to wind this wire on a cylinder whose diameter was less than 40 mm.
- Polysilazane was prepared in a similar manner to Example 1, to form a nitride insulating layer of 7 »m in thickness on the surface of the wire having a metal oxide insulating layer.
- the wire exhibited a breakdown voltage of 1400 V, and it was possible to bend the same to a diameter of 20 mm.
- Another wire was prepared to have a nitride insulating layer of 2 »m in thickness. This wire exhibited a breakdown voltage of 600 V, and it was possible to bend the same to a diameter of 5 mm.
- Fig. 3 is a sectional view showing a wire of this Example having a chromium oxide containing layer, a metal oxide insulating layer provided thereon and a nitride insulating layer formed thereon.
- a nickel-plated layer 22 is provided around a copper wire 21, and a chromium oxide containing layer 23 is provided around the nickel-plated layer 22.
- a metal oxide insulating layer 24 is provided around the chromium oxide containing layer 23, and a nitride insulating layer 25 is provided around the metal oxide insulating layer 24.
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- Engineering & Computer Science (AREA)
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- Inorganic Chemistry (AREA)
- Insulated Conductors (AREA)
Description
- The present invention relates to an insulating member which is applicable to an interconnection wire or a wire for winding in a high vacuum apparatus or an apparatus for a high temperature.
- An insulated wire may be applied to equipment such as heating equipment or a fire alarm, which requires safety under a high temperature. An insulated wire is also employed in an automobile under environment which is heated to a high temperature. Such an insulated wire is generally formed by a conductor which is coated with heat resistant organic resin such as polyimide or fluororesin.
- When an insulated wire is applied to usage requiring high heat resistance or employed under environment requiring a high degree of vacuum, it is impossible to attain sufficient heat resistance or non-outgassing property with only the aforementioned organic coating. In this case, therefore, generally employed is an insulated wire comprising a conductor which passes through an insulator tube of ceramics, an MI cable comprising a conductor which passes through a tube of a heat resistant alloy, such as stainless steel alloy, filled up with fine particles of a metal oxide such as magnesium oxide, or the like.
- On the other hand, a glass braided tube insulated wire employing an insulating member of glass fiber fabric or the like is known as an insulated wire having high heat resistance and flexibility.
- However, an insulated wire coated with organic resin can maintain its insulability merely up to a temperature of about 200½C at the most. Therefore, such an insulated wire cannot be used when insulability is required under a high temperature of at least 200½C.
- Further, the insulated wire which is improved in heat resistance with an insulator tube of ceramics is inferior in flexibility. On the other hand, the MI cable, which is formed by a heat-resistant alloy tube and a conductor, is increased in outer diameter. Thus, the MI cable has a relatively large section with respect to electric energy which is allowed by the conductor passing through the heat-resistant alloy tube. While it is necessary to bend the heat-resistant alloy tube at a prescribed curvature in order to apply the MI cable to a wire for winding which is coiled on a bobbin or the like, such bending operation is difficult. When the MI cable is coiled, further, it is difficult to improve winding density due to the large diameter.
- When the glass braided tube insulated wire is arranged in a prescribed configuration, the glass fiber generates glass dust, which may serve as a gas adsorption source. When the glass braided tube insulated wire is employed under environment which requires a high degree of vacuum, therefore, it is impossible to maintain the high degree of vacuum due to the gas adsorption source provided by the glass dust.
- EP-A-0 416 131 discloses an insulated electric wire comprising a base material having an outer surface and containing a conductor, a chromium oxide containing layer formed on the outer surface of the base material, and an oxide insulating layer formed on the chromium oxide layer. The oxide insulating layer is formed by applying a precursor solution of a metal oxide based on the sol-gel method or an organic acid salt pyrolysis method.
- GB-A-2 182 800 discloses a flat cable comprising a plurality of metallic conductors, a coating of an insulating compound and a continuous polymeric insulating layer. The compound may be nitride. The oxide or nitride coating is provided by sputtering.
- The present invention has been proposed in order to solve the aforementioned problems of the conventional insulated wires, and an object thereof is to provide an insulated wire, which has advantages of: (a) high insulability under high-temperature environment; (b) excellent flexibility; (c) provision of no gas adsorption source; and (d) selectability for combination of a base material and an inorganic insulating layer which is applicable in various ways.
- An insulated wire prepared according to the method of the present invention comprises a base material, a chromium oxide containing layer, and a nitride insulating layer. The base material has an outer surface, and contains a conductor. The chromium oxide containing layer is formed on the outer surface of the base material. The nitride insulating layer is formed on the chromium oxide containing layer. This nitride insulating layer is formed by thermal decomposition of an organic metal polymer.
- According to the present invention, the chromium oxide containing layer is preferably formed by an electrochemical method such as electrolytic plating or electroless plating.
- The chromium oxide containing layer serving as an underlayer for the nitride insulating layer preferably has an outermost layer which serves as an adhesion layer for the nitride insulating layer. To this end, the outermost layer is preferably prepared from CrO3-x (1.5 ≦ x ≦ 2.5). The outermost layer of the chromium oxide containing layer, which is formed by an electrochemical method, is defined by such a layer of chromium oxide having excellent adhesion.
- According to the present invention, the nitride insulating layer preferably contains silicon nitride and/or aluminum nitride.
- According to the present invention, further, the base material is preferably made of copper or copper alloy, in view of high conductivity and a low cost. In consideration of usage under a high temperature, the base material may be formed by a conductor which is coated with nickel, chromium, silver, iron or iron alloy such as stainless steel, or titanium or titanium alloy. In this case, a layer of such a metal or alloy can be formed on a surface of copper or copper alloy by plating or a cladding method.
- According to the present invention, a metal oxide insulating layer may be formed by a sol-gel method between the chromium oxide containing layer and the nitride insulating layer.
- The sol-gel method is a method of forming a sol of a precursor for a metal oxide by hydrolyzing and dehydrating/polycondensing a hydrolyzable compound having metal-oxygen-organic group bonding such as metal alkoxide or metal carboxylic acid ester and forming a metal oxide through a gel by appropriate heat treatment.
- It is known that a chromium-plated layer is formed on a conductor of copper or copper alloy as an excellent adhesion layer. When such a chromium-plated layer is to be coated with an insulating nitride ceramics layer of silicon nitride or the like which is prepared by heat treatment of a precursor solution for a metal oxide, however, such nitride ceramics hardly exhibits adhesion to the chromium-plated layer. The inventors have empirically found this fact. When an insulated wire is prepared by directly forming a thin film of ceramics such as a nitride on the surface of a conductor of copper or the like, the thin film of ceramics, serving as an insulating layer, has insufficient adhesion to the base material.
- According to the present invention, therefore, a chromium oxide containing layer having an outermost layer of chromium oxide is formed on the outer surface of a base material. A layer of insulating nitride ceramics having excellent adhesion is provided on the outermost layer of the chromium oxide containing layer.
- According to the present invention, the chromium oxide containing layer is preferably formed by an electrochemical method, as hereinabove described. When the chromium oxide containing layer is formed by electroplating, the electrolytic bath is preferably prepared by adding a small amount of organic acid to an aqueous solution of chromic acid. This electrolytic bath is different from a Sargent bath, mainly containing chromic acid and sulfuric acid, which is known as an electrolytic bath generally employed for chrome plating, as follows:
- Mineral acid which is mixed into an electrolytic bath is adapted to dissolve chromium oxide formed on a plated surface in electroplating. Therefore, a glossy metal chromium layer is plated through a Sargent bath. In a chromium oxide containing layer formed in the present invention, on the other hand, it is necessary to preferentially deposit and apply chromium oxide. According to the present invention, therefore, organic acid is employe din place of mineral acid.
- According to the present invention, the as-formed layer, which is mainly composed of chromium oxide, preferably has a rough surface, since the same is further coated with an intermediate layer such as a nitride insulating layer or a metal oxide insulating layer. In a preferred embodiment of the present invention, such preferential formation of chromium oxide and the rough surface can be attained by performing plating at a current density which is different from that for general gloss plating. In general, gloss plating is performed at a current density of 10 to 60 A/dm², depending on the treatment temperature. In the preferred embodiment of the present invention, however, a current density of 100 to 200 A/dm² is employed to form a chromium oxide containing layer having a rough surface.
- According to the present invention, the nitride insulating layer is formed by thermally decomposing an organic metal polymer. Such an organic metal polymer can be prepared from alkyl aminosilicate such as polysilazane, for example. This heat treatment is preferably performed under an atmosphere of ammonia or nitrogen jet. The organic metal polymer can be substantially completely decomposed into a nitride by such heat treatment at a temperature of about 700°C.
- In the insulated wire according to the present invention, the chromium oxide containing layer is formed on the outer surface of the base material, and the nitride insulating layer is formed on the chromium oxide containing layer. The chromium oxide containing layer is excellent in adhesion to the base material, as well as to a layer such as the nitride insulating layer or a metal oxide insulating layer. Therefore, high adhesion can be attained as compared with a case of directly forming a nitride insulating layer or a metal oxide insulating layer on the outer surface of the conductor. Thus, the insulated wire according to the present invention has heat resistance and insulability, as well as excellent flexibility.
- The nitride insulating layer formed on the chromium oxide containing layer has a smooth outer surface. Thus, it is possible to obtain a high breakdown voltage which is proportionate to the film thickness and reduce a gas adsorption source, whereby the insulated wire provides a high degree of vacuum in a high vacuum apparatus.
- In the insulated wire according to the present invention, the nitride insulating layer is formed on the chromium oxide containing layer. Since any type of nitride insulating layer can be formed on the chromium oxide containing layer with excellent adhesion, it is possible to combine a nitride insulating layer which is suitably applied in various ways.
- The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
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- Fig. 1 is a sectional view showing Example 1 of the present invention;
- Fig. 2 is a sectional view showing Example 2 of the present invention; and
- Fig. 3 is a sectional view showing Example 3 of the present invention.
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- (a) Formation of Chromium Oxide Containing Layer
Electrolytic plating was performed on the outer surface of a nickel-plated copper wire of 1.8 mm in wire diameter. The electrolyte was prepared to contain 200 g/ℓ of chromic anhydride and 20 g/ℓ of acetic acid. As to plating conditions, the base material was used as a cathode under a bath temperature of 50°C with a current density of 150 A/dm² and a treatment time of 2 minutes. Thus, a chromium oxide containing layer was formed on the outer surface of the nickel-plated copper wire with a thickness of about 1 »m. - (b) Preparation of Coating Solution
15 mℓ of dichlorosilane and 40 mℓ of triethylamine were heated in an autoclave for 5 hours, to prepare polysilazane. The as-obtained polysilazane was diluted with 100 mℓ of tetrahydrofuran, to prepare a coating solution. - (c) Coating
The wire obtained in the above process (a) was dipped in the coating solution obtained in the process (b). The wire, whose outer surface was thus coated with the coating solution, was heated under a nitrogen atmosphere at a temperature of 700°C for 10 minutes. The steps of dipping the wire in the coating solution and heating the same were repeated 10 times. - Thus, an organic metal polymer was applied onto a chromium oxide containing layer and heated to prepare a nitride insulating layer. Fig. 1 shows the as-obtained insulated wire. Referring to Fig. 1, a nickel-plated
layer 2 is formed on the outer surface of acopper wire 1. A chromiumoxide containing layer 3 is formed on the nickel-platedlayer 2. Anitride insulating layer 4 prepared by heat treating a precursor for a metal nitride is provided on the chromiumoxide containing layer 3. In this Example, thenitride insulating layer 4 was made of silicon nitride. Further, a layer defined by the chromiumoxide containing layer 3 and thenitride insulating layer 4 was about 5 »m in thickness. - In order to evaluate insulability of the as-obtained insulated wire, the breakdown voltage was measured. The breakdown voltage of this insulated wire was 500 V under the room temperature, and 300 V under a temperature of 800°C.
- When this insulated wire was wound on the outer peripheral surface of a cylinder of 3 cm in diameter, no crack was caused in the insulating layer.
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- (a) Formation of Chromium Oxide Containing Layer
A copper wire clad with stainless steel (SUS304) was prepared with a wire diameter of 1.8 mm. The stainless steel layer was 200 »m in thickness. This copper wire, clad with stainless steel, was used as a base material, so that its surface was chrome-plated with an electrolyte containing 200 g/ℓ of chromic anhydride and 20 g/ℓ of acetic acid. As to plating conditions, the base material was used as a cathode under a bath temperature of 50°C, with a current density of 150 A/dm² and a treatment time of 2 minutes.
Through such chrome plating, a chromium oxide containing layer was formed on the surface of the copper wire, clad with stainless steel, with a thickness of about 1 »m. - (b) Preparation of Coating Solution
Tris(N-methylamino)methylsilane was heated in an autoclave at 500°C for 3 hours, to prepare polysilazane. 10 g of the as-obtained polysilazane was diluted with 100 mℓ of tetrahydrofuran, naturally cooled at the room temperature, and thereafter mixed with 3 g of aluminum nitride particles of 1.5 »m in nominal particle diameter, to prepare a coating solution. - (c) Coating
The wire obtained in the above process (a) was dipped in the coating solution prepared in the process (b). The wire, whose outer surface was thus coated with the coating solution, was heated at 500°C for 10 minutes. The steps of dipping the wire in the coating solution and heating the same were repeated 10 times. - Thus, a chromium oxide containing layer was coated with an organic metal polymer, and thermally decomposed to form a nitride insulating layer. Fig. 2 shows this insulated wire. Referring to Fig. 2, a
stainless steel layer 12 is formed on the outer surface of acopper wire 11 as a clad layer. A chromiumoxide containing layer 13 is formed on thestainless steel layer 12. Anitride insulating layer 14 is formed on the chromiumoxide containing layer 13.Nitride particles 15, which are aluminum nitride particles, are dispersed in thenitride insulating layer 14. - In this Example, a layer defined by the chromium
oxide containing layer 13 and thenitride insulating layer 14 was 12 »m in thickness. - In order to evaluate insulability of the as-obtained insulated wire, the breakdown voltage was measured. The breakdown voltage of this wire was 900 V under the room temperature, and 700 V under a temperature of 800°C. When this insulated wire was wound on the outer peripheral surface of a cylinder of 15 cm in diameter, no crack was caused in the insulating layer.
- Electrolytic plating was performed on the surface of a nickel-plated copper wire in a similar manner to Example 1, to form a wire of 0.5 mm in wire diameter having a chromium oxide containing layer on its surface. In this wire, the chromium oxide containing layer was 1.0 »m in thickness.
- Then, a solution for forming a metal oxide insulating layer was prepared by a sol-gel method. Nitric acid was added to a solution, containing tetrabutyl orthosilicate, water and isobutyl alcohol in mol ratios of 8:32:60, at a rate of 3/100 mol. This mixture was heated at a temperature of 80°C for 2 hours, to prepare a coating solution. This solution was applied onto the aforementioned wire having a chromium oxide containing layer on its surface and heated in the atmosphere at 600°C for 15 minutes, to form a metal oxide insulating layer of 4 »m in thickness.
- The breakdown voltage of this wire having a metal oxide insulating layer on its surface was 400 V, and it was impossible to wind this wire on a cylinder whose diameter was less than 40 mm.
- Polysilazane was prepared in a similar manner to Example 1, to form a nitride insulating layer of 7 »m in thickness on the surface of the wire having a metal oxide insulating layer. In this case, the wire exhibited a breakdown voltage of 1400 V, and it was possible to bend the same to a diameter of 20 mm.
- Another wire was prepared to have a nitride insulating layer of 2 »m in thickness. This wire exhibited a breakdown voltage of 600 V, and it was possible to bend the same to a diameter of 5 mm.
- Fig. 3 is a sectional view showing a wire of this Example having a chromium oxide containing layer, a metal oxide insulating layer provided thereon and a nitride insulating layer formed thereon. Referring to Fig. 3, a nickel-plated
layer 22 is provided around acopper wire 21, and a chromiumoxide containing layer 23 is provided around the nickel-platedlayer 22. A metaloxide insulating layer 24 is provided around the chromiumoxide containing layer 23, and anitride insulating layer 25 is provided around the metaloxide insulating layer 24.
Claims (8)
- Method for preparing an insulating member comprising:
a base material having an outer surface and containing a conductor (1);
a chromium oxide containing layer (3) formed on said outer surface of said base material; and
a nitride insulating layer (4), wherein said nitride insulating layer (4) is obtained by thermal decomposition of an organic metal polymer and is formed on said chromium oxide containing layer. - The method in accordance with claim 1, characterized in that said insulating member further comprises a metal oxide insulating layer (24), being formed by a sol-gel method, between said chromium oxide containing layer and said nitride insulating layer.
- The method in accordance with claim 1, characterized in that said insulating member is an insulated wire.
- The method in accordance with claim 1, characterized in that said organic metal polymer is alkyl aminosilicate.
- The method in accordance with claim 1, characterized in that said chromium oxide containing layer (3,23) is formed by electrolytic plating.
- The method in accordance with claim 1 characterized in that said nitride insulating layer (4,14) contains silicon nitride and/or aluminum nitride.
- The method in accordance with claim 1, characterized in that said base material (1) is made of copper or copper alloy, or prepared by forming a layer of nickel, chromium or stainless steel on a surface of copper or copper alloy by plating or a cladding method.
- The method in accordance with claim 1, characterized in that fine particles of ceramics (15) are dispersed in said nitride insulating layer.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP96987/91 | 1991-04-26 | ||
JP3096987A JPH04230908A (en) | 1990-06-27 | 1991-04-26 | Insulating member |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0510258A1 EP0510258A1 (en) | 1992-10-28 |
EP0510258B1 true EP0510258B1 (en) | 1995-06-14 |
Family
ID=14179565
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP91121857A Expired - Lifetime EP0510258B1 (en) | 1991-04-26 | 1991-12-19 | Method of making an insulating member |
Country Status (4)
Country | Link |
---|---|
US (1) | US5350638A (en) |
EP (1) | EP0510258B1 (en) |
CA (1) | CA2058147C (en) |
DE (1) | DE69110452T2 (en) |
Families Citing this family (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5636434A (en) * | 1995-02-14 | 1997-06-10 | Sundstrand Corporation | Method of fabricating an electrical coil having an inorganic insulation system |
US6060162A (en) * | 1995-06-08 | 2000-05-09 | Phelps Dodge Industries, Inc. | Pulsed voltage surge resistant magnet wire |
WO1996042089A1 (en) | 1995-06-08 | 1996-12-27 | Weijun Yin | Pulsed voltage surge resistant magnet wire |
US6103382A (en) * | 1997-03-14 | 2000-08-15 | Siemens Westinghouse Power Corporation | Catalyzed mica tapes for electrical insulation |
KR20000015858A (en) * | 1997-03-21 | 2000-03-15 | 크리스티안 반겔 | Mineral-insulated supply line |
US6319604B1 (en) | 1999-07-08 | 2001-11-20 | Phelps Dodge Industries, Inc. | Abrasion resistant coated wire |
DE29913737U1 (en) | 1999-08-06 | 2000-02-10 | Habia Cable GmbH, 40217 Düsseldorf | High temperature resistant cable |
US6914093B2 (en) | 2001-10-16 | 2005-07-05 | Phelps Dodge Industries, Inc. | Polyamideimide composition |
US20040119172A1 (en) * | 2002-12-18 | 2004-06-24 | Downey Susan H. | Packaged IC using insulated wire |
US20080260195A1 (en) * | 2004-02-27 | 2008-10-23 | Plantronics, Inc. | Flexible transmit voice tube |
US7973122B2 (en) * | 2004-06-17 | 2011-07-05 | General Cable Technologies Corporation | Polyamideimide compositions having multifunctional core structures |
US20080193637A1 (en) * | 2006-01-03 | 2008-08-14 | Murray Thomas J | Abrasion resistant coated wire |
US20070151743A1 (en) * | 2006-01-03 | 2007-07-05 | Murray Thomas J | Abrasion resistant coated wire |
US7795538B2 (en) * | 2007-11-06 | 2010-09-14 | Honeywell International Inc. | Flexible insulated wires for use in high temperatures and methods of manufacturing |
US8680397B2 (en) * | 2008-11-03 | 2014-03-25 | Honeywell International Inc. | Attrition-resistant high temperature insulated wires and methods for the making thereof |
US20110147038A1 (en) * | 2009-12-17 | 2011-06-23 | Honeywell International Inc. | Oxidation-resistant high temperature wires and methods for the making thereof |
JP5556720B2 (en) * | 2011-03-28 | 2014-07-23 | 日立金属株式会社 | Insulated wire |
US8884476B2 (en) | 2011-09-23 | 2014-11-11 | General Electric Company | Hybrid dielectric film for high temperature application |
US9859038B2 (en) | 2012-08-10 | 2018-01-02 | General Cable Technologies Corporation | Surface modified overhead conductor |
US10957468B2 (en) | 2013-02-26 | 2021-03-23 | General Cable Technologies Corporation | Coated overhead conductors and methods |
TWI830505B (en) * | 2022-11-21 | 2024-01-21 | 遠東科技大學 | Insulation assembly with ceramic insulating layer formed on concave curved surface thereof and its use for resisting voltage breakdown |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3343984A (en) * | 1962-07-06 | 1967-09-26 | Anaconda Wire & Cable Co | Electrical apparatus, insulating composition therefor and method of making the same |
GB1133333A (en) * | 1965-01-29 | 1968-11-13 | Wilkinson Sword Ltd | Improvements in and relating to electrically insulating coatings |
DE2217769B2 (en) * | 1972-04-13 | 1974-10-03 | Fa. G. Rau, 7530 Pforzheim | Metallic composite body and manufacturing process for this |
US4342814A (en) * | 1978-12-12 | 1982-08-03 | The Fujikura Cable Works, Ltd. | Heat-resistant electrically insulated wires and a method for preparing the same |
JPS5681670A (en) * | 1979-12-06 | 1981-07-03 | Seiko Epson Corp | Exterior parts for watch |
US4431708A (en) * | 1979-12-19 | 1984-02-14 | The United States Of America As Represented By The United States Department Of Energy | Annealed CVD molybdenum thin film surface |
US4500383A (en) * | 1982-02-18 | 1985-02-19 | Kabushiki Kaisha Meidensha | Process for bonding copper or copper-chromium alloy to ceramics, and bonded articles of ceramics and copper or copper-chromium alloy |
GB2182800B (en) * | 1983-07-08 | 1987-12-02 | Raychem Ltd | A flat cable |
JP2890631B2 (en) * | 1989-03-28 | 1999-05-17 | 住友電気工業株式会社 | Insulated wire |
JPH0388215A (en) * | 1989-08-30 | 1991-04-12 | Sumitomo Electric Ind Ltd | Inorganic insulator |
-
1991
- 1991-12-19 EP EP91121857A patent/EP0510258B1/en not_active Expired - Lifetime
- 1991-12-19 US US07/811,459 patent/US5350638A/en not_active Expired - Fee Related
- 1991-12-19 DE DE69110452T patent/DE69110452T2/en not_active Expired - Fee Related
- 1991-12-19 CA CA002058147A patent/CA2058147C/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
DE69110452D1 (en) | 1995-07-20 |
US5350638A (en) | 1994-09-27 |
CA2058147C (en) | 1995-08-01 |
DE69110452T2 (en) | 1995-10-12 |
EP0510258A1 (en) | 1992-10-28 |
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